Electronic Throttle Control Problem

[Doug Manderbach]

I recently purchased a 2004 Ford Explorer XLT 4.0L. As with most used vehicles there are always some problems. I had to replace the coolant temp. sensor and the gauge has not worked correctly since. Also, there has been a significant banging noise during shifts from drive to reverse and vise versa most when the engine is hot. In addition, there has been a noticeable lag in acceleration when turning corners from a stand still.

Since I previously owned a 2002 Ford Explorer XLS I know that some of these kinds of problems can be resolved (or used as a further diagnostic tool), by resetting the PCM, which is something I attempted to do this morning by disconnecting the negative terminal of the battery and using a jumper wire from the positive battery terminal to the disconnected negative battery terminal. This allows the capacitors in the PCM to completely discharge and forces the idle and transmission shift and timing to points to go through a relearn process.

After reconnecting the battery; making sure that all accessories were turned off, I turned the ignition to the on position and waited for the PCM to perform a system sweep. The primary goal being to reset the throttle stop position. When I attempted to turn the engine over what I got was a series of rapid clicks (I'm assuming from the starter), but the engine would not fire. At that point I noticed the the wrench light was lit and after looking in the manual discovered that this indicated a problem with the electronic throttle control.

Can anyone help me. This should be a readily fixable problem. Do I need to clean the throttle body? Or is there some other procedure I have overlooked. This is new to me since as far as I know the wrench light electronic throttle control did not exist on my previous Explorer.

 

[Number4]

Did you mess with the throttle body while it had power?

Could be a PATS issue too.

Usually, loud and rapid clicking indicates a battery that's only strong enough to throw the starter solenoid, but not strong enough to turn the motor. Is the click from under the engine?

 

[Doug Manderbach]

Thanks for the information. I'm not exactly sure what happened, but I went back under the hood to check all the electrical connections which all seemed okay and tried to start the car again and it started right up. However, The "Service engine soon" light came on, so I ran a diagnostic check for trouble codes which returned a P2112 (throttle stuck closed), and a P2104 (forced idle). The latter code returns because of the of the former, so no big deal with that.

Most people would probably start replacing parts but in my opinion that isn't necessarily the best way to go. What I did was to perform a PCM reset again, which will erase the trouble codes, and then test drive the vehicle. If the problem still exists the service engine soon light will come back on. So far (knock on wood), everything is good.

By the way, the water temp. gauge is working just like it should, and there is no lag in power when turning a corner from a stand still. It remains to be seen if the transmission problem has been solved. That might take several days since the pcm is having to relearn shift points and timing all over again.

 

[JJ_04_XLT_V8]

I have a 2004 Explorer V8 XLT that I just purchased with 119,000 miles. It's only issue was acceleration lag from a stop, or when depressing pedal after coasting. You had to depress the pedal 1/2 an inch before moving and if you weren't very careful it would take off like you had punched it. I removed the throttle body and used a full can of throttle body cleaner, scrubbing gently with a soft tooth brush and wiping with a lint free cloth. Prior to removing the throttle body I used a jumper cable from the positive battery to the disconnected negative to drain the PCM for reset. Making sure no electronics were on I reconnected negative and started the vehicle letting it idle for 10 minutes. Then I drove for 10-15 minutes with normal acceleration going through the gears. The vehicle now runs perfectly. Acceleration is normal and immediate.
Good luck!

 

[Stick4503]

I'm interested in this pcm reset procedure. How long does one jump power to the negative cable. Is this an acceptable method (no going to burn something up) please give details.

 

[Number4]

I'm interested in this pcm reset procedure. How long does one jump power to the negative cable. Is this an acceptable method (no going to burn something up) please give details.

http://www.explorerforum.com/forums...etting-the-pcm-after-repairs-are-made.396533/

 

[Stick4503]

Thank you Number4

 

[Tylers02]

Check your tans fluid. I know when mine was low it would shift hard in to reverse/drive, lag/slip on turns. Also had the breaking issue where if I stopped too fast it would act as if it was in neutral then finally catch and take off real fast.

 

[imp]

Thanks for the information. I'm not exactly sure what happened, but I went back under the hood to check all the electrical connections which all seemed okay and tried to start the car again and it started right up. However, The "Service engine soon" light came on, so I ran a diagnostic check for trouble codes which returned a P2112 (throttle stuck closed), and a P2104 (forced idle). The latter code returns because of the of the former, so no big deal with that.

Most people would probably start replacing parts but in my opinion that isn't necessarily the best way to go. What I did was to perform a PCM reset again, which will erase the trouble codes, and then test drive the vehicle. If the problem still exists the service engine soon light will come back on. So far (knock on wood), everything is good.

By the way, the water temp. gauge is working just like it should, and there is no lag in power when turning a corner from a stand still. It remains to be seen if the transmission problem has been solved. That might take several days since the pcm is having to relearn shift points and timing all over again.

@Doug Manderbach
I got both P2112 and P2104 PLUS the one designating "Throttle Plate Stuck OPEN"! Obviously, both conditions, stuck closed
and open, cannot co-exist. The wrench illuminated was a warning of the pending forced idle. Forced idle puts you at a standstill. As it turned out, the initiating cause was a failed ABS Module, which has it's own ability to "stop the car". If your ABS light has not illuminated, obviously your problem is different.

You did not mention "Forced Limited Power", or Limp Home Mode; it's usually "thrown" before Forced Idle, as another warning of pending real trouble. In my case, I heard (and saw) that since PCM only has so many lights to form "warnings" it uses several at once not necessarily related to the base trouble. ABS can be one of them. So is flashing 4X4 HIGH. I looked at innumerable sites, videos, without resolve. One, by a "Ford Tech" (dubious), was throwing Throttle Body codes, like yours, and the guy went to the Rear Wheel Speed Sensor, pulled it out, and it was chewed up! Don't believe everything you see on-line! Another said ONLY Throttle Body failure can throw T.B. codes, replace it. WRONG! ABS can throw them also, by itself. I replaced T.B. and Position Sensor, before I got smarter. Eventually, the ABS Module was found to be the culprit, but only after the ABS light fin ally stayed on no matter what. I replaced the module with a used one.

Forced Idle happened in my shop, fortunately. Rarely are folks so lucky. During the lengthy process I went through, it even tossed in Right Front Wheel Speed Sensor Malfunction, all by alone, no other DTC. Replaced sensor, no resolution, problem same. My Ex runs beautifully now, except for a pesky CEL indicating an HO2S Heater Resistance problem, runs fine with CEL on. Working on that issue now.

Just wanted to share with you, the gamut of unexplainable directions possible. Diagnostics by DTC are not infallible, and lighted icons can be misleading, as one has no knowledge of the factory programmer's intents when turning them on. imp